The boot parameters he is talking about are the kernel command line, which you can set in /flash/cmdline.txt on the RPi. That said, I'm pretty sure there are no VT's available on the RPi even with the tty option.

In case anyone finds this thread later, I'll just state that it's technically possible. I've looked into it in the past without much success. There might be a missing kernel option, or maybe some adjustment to systemd is needed. The debugging shell works fine on the RPi, so in theory it should be possible for systemd to spawn a separate VT if configured correctly.